1. Field of the Invention
The present invention relates to a tire noise reducing system, more particularly to an improved resonance damper disposed in a tire hollow and secured to a wheel rim.
2. Description of Background Art
In recent years, as the mechanical noise from automobiles especially passenger cars is greatly reduced, the tires especially passenger car tires are strongly required to reduce their noise. There are many factors in the tire noise, but a circumferential resonance of the air in the annular tire hollow is a major factor. That is, a ring of air inside the tire continuous around the rim is excited by vibrations during running and resonates in the circumferential direction. Usually, a resonance peak occurs in a frequency range of from 50 to 400 Hz according to the tire size.
In the published Japanese patent JP-B-7-14682, an assembly of a wheel rim and a pneumatic tire mounted thereon is disclosed, wherein a ball-like body which is made of rubber, sponge or the like is put in the annular tire hollow to block the circumferential continuity thereof to control resonance. Such a ball-like body is however, liable to disturb the high-speed rotational balance of the tire because the inner surface of the tire receives a full gravity of the ball-like body which increases as the rotational speed increases. Further, it has a tendency to make it difficult to mount the tire on a wheel rim.
It is therefore, an object of the present invention to provide a tire noise reducing system, in which resonance of in the tire hollow is controlled to reduce tire noise without sacrificing the high-speed balance and rim-mounting operation.
According to the present invention, a tire noise reducing system comprises a wheel rim, a pneumatic tire mounted on the wheel rim to form an annular tire hollow, and a resonance damper disposed in the annular tire hollow, wherein the damper is one of an annular elastic loose band disposed around the rim and a flexible slack strip having a certain length and fixed to the wheel rim at two points so that a portion between the fixed points is slack, whereby a loose portion of the loose band and the slack portion of the slack strip rise by centrifugal force during running to at least partially block the annular tire hollow.
Therefore, the inner surface of the tire receives none or only a part of the gravity and the high-speed rotational balance of the tire becomes greatly improved.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.